Official Luthiers Forum!

jfmkenna wrote"
" If you do a bolt on or even a dove tail you can build the whole box on the work board then set the neck. "

Right. I was taking about the usual Spanish method. I've been using a modification of that for several years, which does allow for neck removal. It's very simple, really. As you say, you start by fitting the neck to a block using either a M&T, dovetail, or bolted joint. The important point is that the neck is fitted in such a way as to produce a 2mm gap between the end on the neck and the block when the neck is plugged in. So far, since I have mostly used this on Classicals as a 'stealth' feature I have opted to glue the neck into the block using 2mm shims. The neck and and block end grain are sized with HHG first, and smoothed off. This really facilitates getting the correct angles on the slots, the proper slot width and uniformity, and makes sliding the sides in a relative snap, since the slots are so clean and smooth. Once the end block is glued to the neck you just go forward with the construction as usual. Remember to cut out the notch at the top of the soundboard above the tenon, so that you can steam off he neck! With a glued-up end bloc of the same material as the neck it would be a real challenge to pick up on this, but if the neck heel and block are glued up with waterproof glue, such as Titebond 3 it's easy to steam things apart. Naturally it's even easier to do this with a bolt-on: just remove the neck itself once you've established the angle, so you don't glue the end of the neck to the sides by accident!

So with the sanding board (4x2 mentioned) does the waist get sanded on the back and top or just the back or not sanded at all?

Thanks, Don. It's kind of you to say all that.

It brings me to the reasons the books were written.

As for many, Cumpiano was a major influence, but we found ultimately that we did nearly everything differently and moved through many different methods before settling on the outside mold, radius dishes, go-bars and bolt-on neck method. When I started writing, there were already many "Build" style books available, but most had gaps, notably in setting up the neck angle, which is such a critical part to getting things right. Nearly all treat the process as a woodworking exercise. It's not. It is woodworking and acoustics. We build guitars to listen to them. Most references will give you the "how", very few give you the "why" and when they do, it is not based on any sort of robust science, so they are often wrong or at best misleading. This necessitates unlearning wrong stuff before learning the right stuff. So, this leads inexorably in one direction....a large two volume set; Design and Build (the why and the how) and a fair bit of science, though the books let you "short circuit" that if you want.

As in any endeavor, knowledge is one of the best tools to have. Gaining the amount of knowledge in the books cannot be done at any lower price if you put a value on your time. AU $255 (~US $180) delivered to your door (check the price of delivering 4kg internationally) represents not a lot of time at today's labor rates. Compare that to the cost of hand/machine tools or materials.

So going back to the OP's initial inquiry:


The advice I would give is do not mix methods, especially if "Quality and usability of the end product is my main priority". It's not so much about getting the side radius to match, it's about getting the neck angle right. Cumpiano's methods have been used by many, but a search in this forum will lead you to discussions concerning the uncertainly of setting the neck angle using that reference. Radius dishes, outside molds etc. can ensure a correct neck angle, but again, a search of this forum will show there are numerous ways of using that tooling to achieve that, so you need to understand what it is you're doing (the why) in order to get it right. How long will it take you to filter through hundreds of internet posts to figure out which of the many methods is most suitable for your circumstances and the relative pro's and con's? And put a cost on your time, because it has one.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

"How long will it take you to filter through hundreds of internet posts to figure out which of the many methods is most suitable for your circumstances and the relative pro's and con's? And put a cost on your time, because it has one."

The time you spend reading and researching won't be wasted as long as you don't let it become such a distraction that it sends you down a bunch of rabbit holes. If you are only looking to build a guitar or two - avoid radius dishes, bending blankets, forms and molds for the most part, and other things that require a substantial investment in tooling. Even the workboard can be simplified by using screws to hold the alignment blocks in place. If later you decide it is a hobby you want to continue then you may want to consider these things.
The advice commonly heard around here is to pick a plan and build to it, and you will probably wind up with a decent instrument.

I would chime in and repeat what I have said here said here many times. (Others May differ). If you want to test the waters of lutherie get a good kit and follow the directions. It works, will be more than an ample challenge, and will result in a decent instrument. Do two or three.

If you are hooked take a building course, it will shave years off your learning curve when starting to build from scratch. You will get a lot more out of the course if you have built a few kits.
The internet can be a quagmire of misinformation and dead ends for the inexperienced builder.

As far as books, Trevor’s is a bargain as far as bang for the buck. If you get a hankering to build obscure vintage ladder and X braced instruments don’t overlook Hans’ offering.

https://www.brentrup.com

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It's not what you don't know that hurts you, it's what you do know that's wrong.

I understand that the neck angle is one of the most important if not the most important step in building a guitar. And I understand it is not easy to achieve the correct angle. But I find it hard to believe that achieving this correct angle would be any harder depending on if I use a mold or a work board to assemble the body of the guitar.

This link
http://www.buildyourguitar.com/resource ... aangle.htm

Gives me pretty much all the information I would need to set the neck angle and of course it would be up to me to fit up the heel block to the body to achieve this but I think I could do it having over 30 years of woodworking experience, and also 25 plus years of ship fitting experience. I guess I’m missing something when I hear how difficult this is.

The difficulty is in the teaching moreso than the doing. If you have a clear understanding of the goal (minimal gap underneath the fingerboard extension when fret plane projection is 1/64-1/16" above the bridge), and the experience to devise a method of accomplishing it, then you're all set.

What makes the teaching difficult is that there are so many different ways to go about getting it right Plus you're building a box that doesn't yet have a fingerboard and bridge on it, so it can get confusing explaining what the measurements should be on that versus on the finished guitar.

Yep. There are at least three pieces of information that I would see as important that are missing from the notes in that link. Plus the part with the heading "Why we shouldn't reduce the bridge height" is totally misleading.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

Yea, I have found that there are so many opinions out there about how to build a guitar. I have no doubt you know exactly what your talking about, and you have gained that knowledge by trail and error and producing a quality instrument on a repeatable basis by using proven techniques. I guess its time to do some more research and try to gain as much knowledge as I can to try and get this done.

Appreciate your time and advice

I built my first acoustic completely from scratch. I had the skills to do the woodwork and a background in engineering so I was able to undersrand what was needed with some studying. The guitar turned out good, not perfect, and I still play it daily.

Everyone's cautions are valid but as long as you make sure you understand the important factors it sounds like you have the skills to make it work. By important factors I mean: neck geometry, required break angles, string spacing, bridge height, saddle height, and intonation. Working off of a good set of plans will help a lot. And of course, you can always ask questions here.

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Steve Smith
"Music is what feelings sound like"

I am a hobby builder and my finished instruments are either given to acquaintances or sold for the cost of materials. I use the workboard for nylon string classical guitars and a mold for steel string dreads. Fun and challenging either way. Enjoy the the ride. It can be more fun than arriving at the destination.

If using Cumpiano, consider going to the link below and pull down/post the errata sheet prior to building, as well as print the revised neck joint pages. The Cumpiano KD screw/barrel nut joint is tolerant of misalignments and quite strong if some cross-grain reinforcement is added (we use CF).

https://www.cumpiano.com/gtt-updates--commentary

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For the times they are a changin'

- Bob Dylan

Does anyone have plans for something similar to the KMG mega mold that has the bar sticking up through the middle? I like the idea of the bar being independent from the mold and you can tilt the mold to get the correct angle to sand the sides to for the correct fingerboard angle.

Coming from making violins; guitars are a whole different animal. There must be a dozen ways to build a guitar. Not as many ways as to leave your lover, but still a lot.

I built a 1/2 scale guitar for the grandsons using just an inside mold. I dished the back a fair amount, and belly a little, using braces with catenary curves in both directions. I couldn't bend the thickish back, (it was for little kids), so I undid the seam, pre-bent them some, re joined the seam, and re-glued it. Then It bent where I wanted with the braces. I just filed the sides until they fit the radius on the back and belly.

I have an arch top almost ready to glue together. It was easy to do without anything fancy, but an outside mold would be easier. A mold seems ideal with an arch top.

I have a fancy mold for a baroque guitar with a rounded back that is made of strips of wood. Not anything like a modern guitar build.

I have some wood to build two flat tops. Maybe a classical and a steel string, I don't know. It seems like they would be easy to do on a board, like a Solera. I have a book and it uses that method. I haven't looked at it in a while. It seems like backs have far more bend in them. Do you need to make 2 boards? I don't know, but they would be easy to do.

I'd say get in and do it. Talk, and finding the perfect method won't do anything for you.

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Why be normal?

Back on topic My recommendation is .....get yourself the two radius dishes if you already have the mold They are not really that expensive to buy, ( consider what your time is worth to you). I build a lot with 15 and 28 and they work fine. Handy to have for radiusing bracing as well. This is your first guitar and they can be resold if you aren't going to build another (Yeah....as if that's going to happen ) Welcome to the world's most expensive and exasperating hobby. Have fun

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Blue Ring Acoustics
blueringacoustics.ca

Except help a person's project result in a successful instrument. FWIW, I think Trevor's Build is the best book out there by far.

Also, I'm all about the mold and dish. It's honestly just easier. I use 30' and 12'.

Honestly a dish and go bars save money.

You can use a half a million cam clamps, cost a ton of money and having to have different kinds to glue one brace and pray the cam clamp does not slip on you (they often do because they apply force in the wrong directions) and you can only glue one brace at a time.

Or you can use a deck and a dish, and basically glue on all the braces at once, not have to worry about slippage as much.

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com